The present invention relates in general to the field of drug assaying techniques, and in particular to a novel high throughput screening assay for screening libraries of candidate compounds.
Recent scientific and technological advances have introduced new opportunities and challenges for drug discovery research. The increased availability of chemical libraries, including peptide and oligonucleotide libraries, and robotic systems enable virtually simultaneous synthesis and testing of hundreds or thousands of compounds. However, while screening of large numbers of candidate compounds is a critical early step in drug discovery and development, it can also be a bottleneck.
High throughput screening (HTS) assays and techniques of various types are typically used to screen chemical libraries consisting of large numbers of small molecules for their ability to suppress or enhance disease processes. Cell-free assays provide, for example, identification of putative drug targets implicated in a specific disease condition, such as a specific enzymatic reaction. Cell-based assays, for example, can provide insights into mechanisms underlying disease pathogenesis, and can also provide information on possible toxicity of candidate compounds. In either case, the goal of such screening is to identify the most likely candidates or “lead compounds” for use in further drug discovery and developments efforts, and not to identify a specific drug. The strength of a particular screening technique lies substantially in its ability to rapidly and efficiently screen large libraries of compounds while remaining cost effective.
Automated HTS assays and techniques and robotic systems for drug discovery have been described. The ability to perform a wide variety of biochemical and molecular biology tests using automated systems is widely known, including the ability to perform tests based using enzymatic activity, ELISA, receptor binding, macromolecular interactions, protein expression, and protein folding and assembly. Screens are typically carried out using multi-well microtiter plates. In drug discovery, a typical example of high throughput capacity is about one hundred to a few hundred plates per week depending on desired number of data points, the time required for all underlying biochemical reactions to occur, and the relative complexity of the scoring system used to determine whether a compound has an effect. A premium therefore exists on methods that simplify and speed detection of assay results.
A small molecular weight compound high throughput screening system using genetically modified Drosophila melanogaster has been described. U.S. Pub. No.: US 2002/0026648 A1. Compounds of interest are microinjected into the open hemolymph of genetically manipulated Drosophila that have been modified with mutations within a selected signaling pathway of interest. However, suitably genetically modified Drosophila are limited in availability and are often costly or difficult to obtain. Further, microinjection of compounds of interest into numerous Drosophila is technically difficult, and is particularly so in a high throughput context where the ability to automate is especially important. In addition, delivery of candidate compounds by microinjection occurs more slowly and can miss orally absorbable drugs.
Accordingly, there remains a need for methods and related articles of manufacture that improve the ability to screen through chemical libraries consisting of large numbers of candidate compounds to rapidly and easily identify the most likely candidate compounds for further drug discovery and research efforts.